The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 24, 2008
Filed:
Jan. 20, 2006
Nobuhiro Miyakawa, Nagano, JP;
Toshiaki Yamagami, Nagano, JP;
Ken Ikuma, Nagano, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
The present invention provides a negatively chargeable spherical toner having: a toner mother particle having a binder resin and a colorant, which has: a number average particle size of from 4.5 to 9 μm; a particle size distribution that has an integrated value of particle sizes of 3 μm or less of 1% or less; and an average sphericity of from 0.95 to 0.99; and an alumina fine particle externally added to the toner mother particle, which has a number average particle size of from 0.1 to 1.0 μm, wherein a work function (Φ) of the toner mother particle is larger than a work function (Φ) of the alumina fine particle by at least 0.4 eV.